The Motion Picture Expert Group (MPEG) develops standards concerning audiovisual content. One component of the MPEG standard scheme includes MPEG-7 standards which are directed to providing descriptions of audiovisual content that may be of interest to the user. Specifically, the MPEG-7 standards are developed to standardize information describing the audiovisual content. The MPEG-7 standards may be used in various areas, including storage and retrieval of audiovisual items from databases, broadcast media selection, tele-shopping, multimedia presentations, personalized news service on the Internet, etc.
MPEG-7 standards rely on a set of generic audiovisual description schemes (GAVDS). According to the GAVDS, descriptions are divided into syntactic descriptions and semantic descriptions. A syntactic description is typically concerned with physical properties of the content. Syntactic descriptions may include such video features as, for example, shape, color, position, or texture, and such audio features as, for example, key, mood, or tempo. A semantic description represents human interpretation of the audiovisual content, e.g., a description such as: “a duck hiding behind a tree and a car passing by in the background.”
The purpose of the GAVDS is to provide a set of tools in terms of descriptions and description schemes. Using the above division among descriptions, the access to the descriptions is provided using indexes that are built from the semantic descriptions that point into the syntactic descriptions. However, this structure has several deficiencies. First, in some situations, relevant parts of a description of a piece of audiovisual content cannot be located together. For example, when a “semantic” description describes a “syntactic” audiovisual object, the description must be constructed separately and attached to the object by links, regardless of the description's intended purpose or method of generation. In addition, the GAVDS categories are not pure (e.g., a segment designation that contains semantic meaning). As a result, it may be difficult to classify a description as being either semantic or syntactic, which may, in turn, cause an unnecessary proliferation of description schemes. Furthermore, the above structure forces the GAVDS to be a single piece of content, thereby negatively affecting the speed of locating a required description.
Therefore, it would be advantageous to improve the existing structure of the description scheme in order to enable fast and efficient access to information describing audiovisual content that is of interest to the user.